About a year ago some Hamtaro socks were in promotion at our local grocery store. I had never heard of Hamtaro and stuff but found the creatures to be quite funny so I bought them anyway.
I was quite surprised when I suddenly got a game called Hamtaro: Rainbow Rescue in my hands, I suddenly realised with what I could associate my socks.

From the moment you start up Hamtaro, happy colors and sounds are around you. Unfortunately this joy doesn't last long as Ham-Ham Bo drops off his rainbow and not only does he hurt his butt but also his colors disappear. With Hamtaro and his friends you'll have to go searching through the different levels for the seven colors of the rainbow.

From the club house you leave towards a level where you have to look for one of the wanted ingredients to fix Bo's color-umbrella. Not only do you have to solve in-game puzzles and play "HAM-Games", but also you'll have to find other Ham-Hams that are lost or in some way have wandered off from the group. This sometimes makes that you have to follow the same path a bit too often but in general it isn't too annoying.

All living characters that you can encounter in the levels can be talked with, one time such a conversation makes a bit more sense than another. Every time your own Ham-Ham's call out Hamha (hello) and make their happy little dance, you will immediately become more joyful.
Also the expression "Ookwee" (from my favorite Ham-Ham Penelope) will be etched in your mind after having played this game.

While going from mission to mission you need to collect as many stickers as possible. Sometimes you'll just run into these but most of the time you'll need to collect as many carrots, sunflower pits and pink candy as possible which you can trade in for stickers or other items like color plates.
The Ham-games give you points and with each 100 that you have earned you'll automatically receive a new sticker. These mini-games vary from puzzles and platform-like games to memory exercises and multiple-choice questions. Sometimes they're a bit more difficult than expected but by turning in a wallnut you can skip that specific mini-game. If you do that you won't receive points or a sticker though.

Outside of the main game you can have fun with the color plates and when you link up your GBA with another you can share these aswell as the stickers. Due to lacking of another Hamtaro-fan with GBA and a second game I unfortunately couldn't test this out myself.

I was peculiarly interested in the ending of the game so I didn't really concentrate on collecting points and stickers. I won't tell the ending but I can say it's a very addictive game that makes you completely happy.
Even for those that are a bit older, the game has a lot of humour. It's created very playful and happy which shows a lot in the dialogues, colors, sounds and of course the Ham-Ham's themselves.

The box states that this is a 3+ game but then your 3-year old has to be able to read as otherwise he won't be able to understand a thing. Even worse, you'll need to master the English or another foreign language as the game isn't available in Dutch. However, this is the only downpoint I could find so I suggest you now run to the store to get Hamtaro: Rainbow Rescue so that we can exchange stickers!